The reason you might be privy to this bad advice is because it is only recently that the search engine spiders have started penalizing people's sites for the technique so it is still an essential part of many Internet guru text books that are sold on the Internet. The idea was to use visual design and color to trick the human eye into not seeing a page loaded with keywords but to make it seem to the search engines that you are loaded with keywords. For instance if the background of your web page is bright blue then you would put your normal non optimized language in blue and then optimize the site with keywords by adding text in the same blue as the background. Your human readers would be unable to see this text but the search engine spiders would see the entire text and boost your rankings as a result. Google and other big search engine spiders have not put an end to this.

The weird consequence of all of this is that the spider engine algorithms have now been programmed to penalize sites that do this but unfortunately the consequence is sometimes to penalize a site that has the same color type and same color page in it. To avoid potential problems with this type of design (and of course accidentally getting yourself blacklisted) never put your text in the same range of hues as your background text. In fact, the optimum page colors when it comes to search engine optimization are always probably going to be plain old boring black text on white.